Map of Chinook populations in Puget Sound.

Project Title

A landscape scale analysis of Chinook salmon spawning and rearing habitats in Puget Sound

Description

The ability of freshwater habitat to support and sustain healthy populations of salmon has changed markedly from historical conditions. In Puget Sound, where Chinook are threatened, we have developed methods for quantifying habitats used by adult and juvenile life stages for both current and historical conditions. Our approach for deriving coarse-scale estimates of existing Chinook spawning habitat utilizes existing geospatial data coupled with empirical data from previous studies to develop a spawning suitability index for individual stream reaches. This index is derived using stream gradient, estimated bank full width, and riparian condition. The validity of this approach is being assessed using information from ongoing fine-scale analyses and local watershed groups. Preliminary results indicate that anthropogenic barriers exclude adult Chinook from large areas of formerly accessible spawning habitat, and that changes in riparian conditions have reduced the spawning potential of many reaches. Ultimately our results will be used to compare the current and historical potential of Puget Sound watersheds to support Chinook salmon, and to assist local watershed groups in setting protection and restoration goals.

Investigators

Beth Sanderson, Jeremy Davies ( NWFSC), Krista Bartz (NWFSC), Kerry Lagueux (New England Aquarium), Hiroo Imaki (UW) Mary Ruckelshaus (NWFSC), and Tim Beechie (NWFSC)

Support

NWFSC

Project Status

Adult capacity analyses complete (writing in progress); juvenile habitat analyses in development

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